1. Field of the Disclosure
The present disclosure relates generally to data processing devices, and more particularly, to error detection at data processing devices.
2. Description of the Related Art
Advancements in the performance and computational capabilities of integrated circuit (IC) data processing devices are often the result of a corresponding reduction in the size of the transistors, conductors, and other components that make up the devices. Furthermore, the operating voltage of modern IC data processing devices is typically minimized to increase the operating frequency and to reduce power dissipation of the devices. Because of these changes, conductors and storage nodes included at the data processing device have correspondingly low capacitance, and therefore are capable of storing only a small amount of energy. Thus, the device is increasingly susceptible to soft errors. A soft error can result from the interaction of an energetic neutron or alpha particle with the small conductors and charge storage nodes of a data processing device. Neutrons typically originate from cosmic rays, and alpha particles originate from materials present in the integrated circuit package and bonding materials.
A combination of the capacitance and the voltage at a node of a device is described by a critical charge parameter, Qcrit, which is the minimum electron charge disturbance needed to change the logic level at the node. Larger Qcrit values are associated with fewer soft errors. Unfortunately, signals at a node with a larger Qcrit value will transition slower and dissipate more power than a node with a relatively smaller Qcrit value. Reduction in the feature size of transistor and conductors at the data processing device and a reduction in the operating voltage decreases Qcrit. Thus, the incidence of soft errors increases as chip technology advances. In a logic circuit, Qcrit is defined as the minimum amount of induced charge required at a circuit node to cause a voltage pulse to propagate from that node to the output of a corresponding logic gate, and be of sufficient duration and magnitude for an error to be subsequently stored at a down-stream latch device. Error correction codes and associated circuitry can be used to detect and sometimes correct soft errors, but is not practical for use at the large number of latches that make up computational logic blocks of a data processing device.